August is not a month for much bee work. It is too hot and colonies can be a bit testy. Keep water nearby and give them some supplemental shade in the afternoon if you are concerned. August however is for mite monitoring – the month to determine how the bees are doing with keeping a lid on varroa mites.
Mite monitoring is good bee stewardship. It lets you know precisely how the bees are doing and how successful everything you may have done for mite management so far this season has helped the bees. Monitoring means taking the pulse of the colony – are they holding their own or are the mites getting to potentially harmfully high levels?
Mite monitoring can be done in a number of ways. Looking for phoretic mites on adult bodies or percent of drone brood cells with developing mites is highly interventive as we have to open the hive but it also is not very accurate – it says the hive has mites but not how many mites! Using a sticky board is less disruptive, especially if you have a screen bottom board or bottom that has a built-in sticky board for monitoring, but is tedious in counting the mites, takes two visits (to put the boards in and then remove them) and, for some, the mites are difficult to count, especially with lots of hive debris. It is a measure of colony mite load.
Washing adult bees of mites is a measure of colony mite intensity. It does necessitate entering the colony as we prefer to take a sample of 300 adult bees from 1-2 brood frames. It is however the best measure of how your bees and you with any mite reduction efforts are doing in resisting/tolerating mites. [for a review of mite sampling and what numbers mean, I suggest looking at my HONEY BEE BIOLOGY AND BEEKEEPING, revised edition, Chapter 19, pages 315-317. I can send you this section electronically if you drop me an email request at dmcaron@udel.edu]
Here in summary is the best way to take an adult bee sample and determine colony mite intensity:
- Remove ~300 adult bees from brood comb into a mason jar (to the ½ cup mark) in which you have replaced the lid with an 8-mesh screen, fit snugly into the ring closure. Do this by moving wide-mouthed jar down the comb so bees “fall into” the jar. Alternately shake 2-3 brood frames into a bucket and then scoop out ½ cup bees into a jar with solid lid replaced by 8-mesh screen
- Place modified screen lid on jar; tap jar to settle bees on bottom.
- Place 2 tablespoons of powdered sugar onto bees (through screening). Alternately, add rubbing alcohol thru the screen top to kill the bees.
- Close jar and shake/roll bees for 20–‐30 seconds. Set aside for 30 seconds so sugar ends up coating bees (you do not need to do this if you use alcohol]. Re-shake vigorously another 20-30 seconds.
- Invert and shake sugar and mites from jar onto white collecting paper or pan [if using alcohol pour liquid into a white pan]. Mist spray to dissolve sugar if you used sugar.
- Count the number of mites and calculate the percent infestation of adult workers: (# mites/#bees divided by 100]. If unsure you have a thorough count, repeat with more sugar/alcohol.
- If infestation is over 2% (i.e more than 6 mites, assuming 300 adult bees] consider the hive at risk and if mite number is approaching or over 5% (10-15 mites) consider immediately using a mite reduction management chemical (Apivar, Apiguard, ApiLife Var, Mags, Hopguard II] or dividing the colony into several smaller units [brood break]. Follow up with another sample at end of recommended treatment period. (Apivar treatment takes 42-56 days).